Flexible coupling



April 2, 1946. L. SLOAN 2,397,700

FLEXIBLE COUPLING Filed Nov. 26, 1945 2 Sheet s-Sheet 1 April 2, 1946. ISLOAN FLEXIBLE COUPLING Filed Nov. 26, 1943 2 Sheets-Sheet 2 I INVENTOR.

4w My ATTQPNL'YJ Patented Apr. 2, 1946 i umr o STATES PATENT OFFICEFLEXIBLE COUPLING Lon Sloan, Cleveland, Ohio Application November 26,1943, Serial No. 511,766

6 Claims.

The present invention, like that which constitutes the subject matter ofPatent 2,196,841, granted to me April 9, 1940, relates to flexiblecouplings; and the constructions disclosed in said Patent are thenearest to my present improvements of any prior art of which I haveknowledge.

As is known to those familiar with the subject, flexible couplings serveas torque transmitting connections between driving and driven members orshafts, and yield to any angular or ofiset parallel misalignment, or acombination of angular and oflset misalignment, between said members orshafts.

Among the objects of my present invention are to simplify theconstruction, reduce the manufacturing cost, and facilitate the assemblyof couplings-of the kindin question, while maintaining the highesttorque transmitting efliciency and providing ample capacity for anymisalignment, as well as for any radial and axial vibration, encounteredin practice.

Further objects are to provide a flexible coupling wherein practicallyperfect dynamic balance is obtained; and to provide a coupling of theclass referred to that is very durable; that is practically immune fromdisorder; that requires no lubrication, and that demands no attentionafter being properly installed.

A further and more specific object of the invention is the provision ofa flexible coupling comprising end members for rigid connection with thedriving and driven members, respectively; a flexible torque transmittingelement in the nature of a spiral spring surrounding and substantiallyconcentric with the axes of said end members and through which they havea yielding driving connection permitting limited relative movementbetween them in all directions, and means exterior of said flexibleelement by which a delayed positive drive is efiected between said endmembers upon a predetermined torsional deflection of said element.

Other objects and advantages will appear as I proceed to describe theinvention by reference to the accompanying drawings wherein Fig. 1 is aside elevational view, partly in section, of a flexibie couplingembodying the invention, this construction being especially suited tolarge size couplings and being adapted to abutting shaft installations;Fig. 2 is an end elevation of the coupling, the shaft appearing in saidview being in section; Fig. 3 is a side elevation, on a smaller scale,of one of the flexible elements or springs; Fig. 4 is a longitudinalsection, on the line 44,oi Fig. 5 (with the sectioned areas disposed ina common plane), through a modified form of the invention adapted toinstallations wherein the shafts are spaced a substantial distanceapart, the present construction being especially appropriate for sma s eco plin s, and Fig. 5 is a section on the line 5-5 of Fig. 4.

In the construction illustrated in Figs. 1 to 3, end members, designatedgenerallyby the reference numerals l and 2, are applied to the adjacentends of shafts A and B, either of which may be regarded the drivingmember, and the other the driven member. The end members I, and 2 aredesirably identical, and each comprises a cylindrical hub 5 and an endflange 5, the latter being provided with a series of counterbored holesI. The hubs 5 have bores that fit the shafts A and B to which the hubsare secured against rotation by keys 8. The external diameter of each ofthe hubs 5 is enlarged adjacent the flange B to provide a cylindricalseat 9.

Surrounding each hub 5 is a flexible torque transmitting element l0,shown in side elevation on a reduced scale in Fig. 3.

Each of the torque transmitting elements desirably consists of acasting, forging or the like, and, in accordance with the methoddescribed and claimed in an application filed by myself concurrentlyherewith, is produced 'from an inherently resilient material such, forexample, as some of the alloy cast irons that are now being extensivelyproduced and which possess physical being surrounded by a spiral slot l3whose terminals are disposed on the same side of the body in alignmentlongitudinally thereof. This insures perfect dynamic balanceof theelement,

assuming the same to be absolutely symmetrical about its longitudinalaxis. The slot l3 reduces the portion of the body ll intermediate itsextreme ends to a flexible helix l4, remembering that the element isformed from inherently resillent material. The end of the body remotefrom the flange l2 fits snugly within the angle between the cylindricalseat 9 and the inner surface of the flange 6 of the end member wherewiththe element is associated. Said end of the body II is provided withtapped holes that register with the previously mentioned holes I of theflange 6; and screws l5, that are projected through the holes I and arescrewed into those of the body,

secure the torque transmitting element ID to the corresponding endmember.

The two torque transmitting elements in may be identical in form, andreversed with respect to each other, or the helixes M of said elementsvmay be of opposite pitch so that in the action of the coupling, as willhereinafter more fully appear, one helix will expand as the othercontracts.

The opposed torque transmitting elements are arranged with their endflanges |2 in contact with each other, and surrounding the bodies H ofsaid elements, are cylindrical casings |8 provided with flanged endwalls l9 that bear against the flanges l2. Said end walls and flanges I2have registering holes through which bolts 20 are projected, the heads2| of which, and the nuts 22 that are applied to their threaded ends,are virtually enclosed by the peripheral flanges of the walls IS.

The bodies H of the torque transmitting elements I are provided withlongitudinal peripheral splines 25 that normally repose substantiallycentrally within similarly disposed grooves 26 of the casings l8, thelateral edges of the splines 25 being spaced an appreciable distancefrom the side walls of the grooves 26; and throughout their opposedcylindrical surfaces, the torque transmitting elements and casings arespaced apart a suificient distance to allow the lateral or radial playrequisite to a proper action of the coupling.

I may cite as an example of the many uses of flexible couplings theconnection between the shaft of a Diesel engine and that of acompressor,

plunger pump or other unit driven by the engine. Regardless of the careexercised in setting up the equipment, misalignment between the drivingand driven members of shafts almost invariably initially exists orultimately develops. Accordingly, provision has to be made for such acontingency in every case where the machinery is of substantialsize andform. It will be apparent from its construction that the'flexiblecoupling above described will readily yield to angular and/or oflsetmisalignment between the driving and driven members represented by theshafts A and B, as well as to any axial or radial vibration of themembers .or shafts, the flexible elements actually having the capacityfor misalignment and vibration far in excess of any practical demand,wherefore, in practice, flexing of the elements to compensate forirrgularities in the action of the driving and driven members isconfined to the initial stage of distortion wherein opposition to suchaction is at the minimum.

It is also apparent from the nature of the construction that the helixesH are stiff and capable of transmitting the full torque load withoutappreciable torsional deflection excepting at the moment of starting orstopping, when any shocks that would otherwise occur between theconnected shafts or members will be absorbed by the helixes as stored upenergy to be subsequently released. When momentary differences do occurin the relative speeds of the driving and driven members or shafts, aswhen starting or stopping, the helixes are protected against unduedistortion and overload by engagement of the splines 25 of the powertransmitting elements with the abutments provided by the side walls ofthe grooves 26 of the casings l8. These coacting parts provide a delayedaction positive driving connection between the driving and drivenmembers upon predetermined torsional deflection of the helixes.

Attention is also directed to the fact that the casings l8 areyieldingly suspended by the torque transmitting elements l0.Consequently, at high speeds, a gyroscopic action will be set up thatwill tend to keep the exterior of the coupling in a substantiallyconstant position notwithstanding slight variations in the position ofthe end members due to misalignment,

In the embodiment of the invention illustrated in Figs. 4 and 5, asingle power transmitting element is employed; and, incidentally, theend members are designed for attachment to driving or driven members orshafts that are spaced a considerable distance apart.

The driving and driven members are designated C and D, and to them aresplined the hubs 30 of the flange-like end members 3| and-32. Engagedwith the inner face of the end member 3|, and centered thereon by ashallow cylindrical boss 33, is the annular end wall 34 of a cylindricalcasing 35, formed on its inner side with alternate longitudinal splines36 and relatively wide grooves 31. Occupying the casing 35, with itsperiphery suitably spaced from the inner surface of the casing is thehollow cylindrical power transmitting element 40 having a spiral slot 4|that terminates short of the ends of the element and reduces the portionof the element intermediate said ends to threaded into tapped holes inthe end of the element 42, the heads of said screws occupyingcounterbores in the outer face of the end member 3|.

The opposite end of the power transmitting element is engaged with theinner face of the end member 32 and is centered thereon by a shallowcylindrical boss that fits within the bore of the element 40. The endmember 32 is connected to the adjacent end of said element by screws 49that are projected through counterbored holes in the and member and arethreaded into tapped holes in the power transmitting element. Theperiphery of the power transmitting element is made up of alternatelongitudinal grooves 50 and relatively broader splines 5|, the formerloosely receiving the splines 36 of the casing, while the splines 5|occupy the grooves 31 with their lateral edges normally spaced anappreciable distance from the side walls of said grooves.

The end of the shaft D is shown as provided with a threaded axial stud53 that is extended through a washer 54 which bears, adjacent its edge,against the boss 48 of the end member 32, and by means of a nut 55 thatis threaded onto the stud 53, the end of the shaft D may be drawn firmlyinto the hub of the end member 32.

It is obvious from the construction above described that the helix 42will yield'to any angular or offset misalignment between the driving anddriven members and also to any radial or axial vibration. In the case ofmomentary differences in the speeds of the driving and driven members,energy will be stored in the helix, subsequently to be spent in the formof transmitted power. Upon a predetermined degree of torsionaldeflection of the helix resulting from suchdifierences in speed, theinterengaging splines of the casing 35 and the torque transmittingelement 40 will coact to establish a positive driving connection betweenthe end members of the coupling,

casing surrounding said ,element and including a part interposed betweenthe opposite end of said element and the other end member, meanssecuring the last mentioned end member and said part to the adjacent endof the element the portion of said element intermediate its ends beingflexible. said element having longitudinal peripheral grooves and thecasing having correspondingly disposed splines on its interior thatoccupy said grooves with their surfaces normally spaced a substantialdistance from the opposed surfaces of the grooves.

3. A flexible coupling comprising end members for attachment to adriving member and a driven member, respectively, said end members beingspaced apart along the axis of the coupling, a hollow cylindrical torquetransmitting means surrounding said axis and secured at its ends to.said end members, the portion of said means intermediate its ends beingflexible, and a casing surrounding said means and supported solelythereby, the casing and said means having cooperating parts throughwhich a positive driving connection is established between the endmembers upon a predetermined degree of torsional deflection of theaforesaid flexible portions.

4. A flexible coupling comprising end members for-attachment to adriving member and a driven member, respectively, said end members beingspaced apart along the axis of the coupling, two

transmitting element and th nd members of 5 hollow cylindrical torquetransmitting elements I the coupling is that different end members mayaxially aligned and in substantially concentric be selected forincorporationin a coupling accordrelation to the aforesaid axis, saidelements having to whether the shafts are arranged in abutting ing theiradjacent ends engaged with each other relation, as in Fig. i, or inspaced relation, as in and their opposite ends secured to the respectiveFig. 4. Also, end members having different size end members, the portionof each element interbores may be selected according to the size of themediate its ends being flexible, casings surround shafts wherewith thecoupling is to be employed. ing said elements and connected together andto Having thus described my invention, what I said elements in theregion of the adjacent enclaim is: gaging ends of the elements, thecasing and said i. A flexible coupling comprising end members elementshaving splines arranged to contact one for attachment to a drivingmember and a driven an t r ut n r ally s aced apart f r effectingmember. respectively, said and members being positive drivingconnections between the end spaced apart along the axis of the coupling,a holmembers upon a predetermined degree of torlow cylindrical torquetransmitting element sursional deflection of the aforesaid flexibleportions rounding said axis and disposed between said end of the saidelements. members, means connecting one of the end mem 5. A flexiblecoupling comprising end members bers to the adjacent end of saidelement, a casing for attachment to a driving member and a drivensurrounding said element and including a part member, respectively, saidmembers being spaced interposed between the opposite end of saideleapart along the axis of the coupling, two hollow ment and the otherend member, means securing cylindrical torque transmitting elementsarranged the last mentioned end member and said part to in substantiallyaxial alignment with their ad the adjacent end of the element, theportion of jacent ends engaged with each other and in subsaid elementintermediate its ends being flexible, stantially concentric relation tothe aforesaid and splines on the exterior of said'element and axis, thesaid adjacent ends being characterized by the interior of said casingarranged for engage- 3o radially extended flanges, the end members beingment with each other but normally spaced apart provided with seats towhich are fltted the ends of a substantial distance. said elementsremote from said flanges, means se- 2. A flexible coupling comprisingend members curing said end members to the adjacent ends oi forattachment to a driving member and a driven said elements. a cylindricalcasing surrounding member, respectively. said end members being eachelement and radially spaced therefrom, each spaced apart along the axisof the coupling, a casing having an end wall engaged with theradialhoilow cylindrical torque transmitting element ly extended flangeof the corresponding element. surrounding said axis and disposed betweensaid means securing together the flanges of said eleend members, meansconnecting one of the end ments and the end walls of the two casings,the members to the adjacent end of said element, a 40 elements beingprovided with longitudinal peripheral grooves and the casings havinginternal similarly disposed splines that occupy said grooves and fromthe walls of which the opposed surfaces of said splines are normallyspaced a substantial distance.

6. A flexible coupling comprising a structure including end members forattachment to a driving member and a driven member, respectively. saidend members being spaced apart along the axis of the coupling, a hollowcylindrical torque transmitting means surrounding said axis and securedat its ends to said end members, the portion of said means intermediateits ends being flexible, and a casing incorporated in the structure andenclosing said means, said casing and the said means having cooperatingparts disposed longitudinally of the coupling and extendingsubstantially from one to the other of said end members through which apositive driving connection so is established between the end membersupon a predetermined degree of torsional deflection of the aforesaidflexible portion.

LON SLOAN.

